【作者】 李沛刚；

【导师】 冯显英；

【作者基本信息】 山东大学 ， 机械设计理论， 2010， 博士

【摘要】 机械产品概念设计是产品设计过程中极其重要、最具有创造性的阶段,产品概念设计方案的质量决定了产品最终价值的80%以上。由于传统产品设计建模技术主要集中于物理建模和几何表示方面,致使产品概念设计阶段缺乏有力的技术支持。如何在设计理论和方法的指导下,对概念设计知识、概念设计过程知识进行有效的分类整理、特性提取、信息建模,并通过合理的人机协调策略,构建计算机辅助概念设计体系是当今学者研究热点之一。在综述概念设计研究现状与进展的基础上,为解决机械产品概念设计过程中存在的问题,本文围绕着概念设计过程建模、产品信息描述等这些概念设计中的关键问题,对概念设计方案过程设计模型及求解策略、概念设计产品描述模型以及定性空间构型设计等方面进行了深入研究。本文主要研究工作集中在以下几个方面：(1)首先阐述了基于功构模式的概念设计理论基础—分解重构原理、广义定位原理、生长型设计理论。分解重构原理在哲学层次上揭示了发明创造的本质；广义定位原理在理论层上阐明了机械产品设计中每一零件都应遵循的约束法则；生长型设计理论借鉴生物生长机制,在方法层上阐述了机械产品设计进化设计的一般原则。在此基础上,结合公理化概念过程设计模型—Zigzag模型,提出了基于功能—功构模式—结构的概念过程设计模型。基于功能—功构模式—结构的概念过程设计模型面向TOP-DOWN,以功构模式为映射媒介,使功能分解和结构重构并行进行。并对该模型内容进行了新的3级层次分解：产品设计专用层、产品设计通用层(即机构学层)、产品设计基础层(标准件层)。设计层次越深,产品设计知识的相关性越低,创新能力也越差,在不同的设计过程层次,采用了不同设计策略。阐明了设计问题是一个认知过程,设计的过程是一个结构细化的过程。在设计知识支撑下,设计信息随着设计过程的展开逐渐增加,体现了人类认知和思维的规律；同时也表明从产品概念原型到设计方案的完成,每一个阶段都反映了设计对象的结构生长过程。(2)在分析现有文献提出的功能表达模型基础上,探讨了一种创新的功能信息表达模型。该模型包含功能行为表达集、功能行为参数集和功能约束特征集3部分,适用于产品级、传动链级、传动级的三层结构功能描述,在重用过程中可以重新进行概念扩展,具有相当大的灵活性。功能行为集是功能分解的主要原动力,功能约束特征集是结构重构的知识基础。功能建模是概念设计中的核心问题之一,功能信息自身的特点决定了它在计算机中表达的艰巨性。为此,讨论了用户需求的建模问题、用户需求的采集、组织、加工以及需求的特点,为用户功能的建模提供可能。同时,对围绕与功能建模有关的概念、名词术语等(如功能、质量、性能等)进行了讨论和重新定义,赋予了新的含义。阐述了功能信息表达模型在设计中的分解重构过程,并提出功能约束关联因子模型,分析了性能因子在分解重构中的作用、分解、重用方法。此概念在产品自动化设计中,为寻求提高产品的每项性能提供可能,不仅对创新设计、适应性设计有重要意义,也为反求概念设计提供了新的思路。(3)在分解重构原理和广义定位原理的基础上,详细描述了概念设计产品整个生命周期中的最小信息单元功能表面。介绍了概念设计产品功能表面的分类,分析了功能表面、结构、定位之间的关系。在此基础上,系统阐述了概念设计产品的基本信息单元功构模式和其在产品概念设计中的作用。建立了功能—功构模式—结构的映射模型,采用功构模式作为物理载体,在更深的层次上实现功能到结构的信息传递。从而使产品信息表达更完备,组织更灵活,概念上、理论上更加严谨、科学。分析了功构模式在功能驱动下的进化生长进程,引入了功构模式传动链设计的一般推理规则。采用面向对象技术,研究了功构模式数据结构和分类编码。把功构模式分类编码划分为表示符、识别码、功能特性码三部分。其中,识别码为零件分类编码,是主动类型。当在一外部消息驱动时,识别码调用自己,可执行一个检索任务。基于逆向工程理论,提出了基于功构模式的零件功能因子与概念结构因子的获取方法,分析了基于逆向工程产品设计过程功构模式的重构方法。(4)在生长型和公理化设计理论基础上,建立了机械产品概念设计推理模型,有效解决了由功能—功构模式的映射。同时,针对概念设计阶段设计信息无法量化、设计结果不确定等问题,提出了基于Delphi层次分析法、信息最小化分析法、标准差法三层概念设计原理解模糊评价体系。在解决功能—结构映射病态性的同时,从整体上优化产品概念设计方案。建立了基于虚传动链的PART-NET装配模型,表达了零件与零件之间、表面与表面之间的装配关系,实现了零件之间的全相关性。提出了基于实例的进化检索机制,应用层次分析法确定匹配度权值系数,进而建立运动和结构匹配度函数。阐述了基于实例的检索流程,有效解决了设计知识表示和实体结构转换问题,有利于计算机辅助概念设计工具的开发。(5)开发了面向装配的计算机辅助概念设计系统—FM-BDARFAD,建立了以产品结构为中心的支持并行设计的产品结构创成过程,实现了产品结构从无到有、零件从少到多的生成设计过程,真正体现了TOP-DOWN设计过程。开发的面向装配的FM-BDARFAD计算机辅助概念设计系统,基于生长型设计理论的思想,从产品设计需求出发,交互式创成产品概念原型,并经过功能的分解重构获得产品概念的结构设计方案。以传动链设计为核心,反应了设计信息由少到多、由简到繁的综合过程,构成从无序到有序、从低级到高级的产品设计生命周期。该系统包括需求管理模块、功能管理模块、方案推理模块、方案评价模块、虚拟仿真模块、实体匹配模块、产品逆向求解模块、公差求解模块、信息管理模块、安全管理模块等功能模块。给出了多功能腰脊椎牵引床设计实例,详细描述了其功能分解和产品进化的过程。实例研究表明,基于提出的功能—功构模式—结构的映射模型,建立支持产品概念设计的产品过程设计模型是有效可行的,从而为计算机辅助产品概念设计提供了一个新思路。更多还原

【Abstract】 Conceptual design of mechanical products is the extremely important and most creative stage in the process of product design, the scheme’s quality of which determines final value of products over 80%. The modelling technology of traditional product design mainly focused on the physical modelling and geometric representation aspect, which resulted in products conceptual design phase lacked of strong technical support. In the guidance of design theory and method, how to carry out effective sorting task, feature extraction and information modelling to conceptual design and conceptual design process knowledge, and then build computer aided conceptual design system through reasonable man-machine coordinate strategy, is one of the research hotspots of today’s scholars. Based on the research status and progress of overview conceptual design, in order to solve the problems existing in the process of conceptual design of mechanical products, this paper centers on the key problems of conceptual design, such as the modelling of conceptual design process, and description of product information, and carries out in-depth study in the design modell and solution strategy of conceptual design scheme process, description modell of conceptual design products and the configuration design of qualitative space etc. This paper mainly focuses on the following aspects:1) Theoretical basis of conceptual design, such as decomposition and reconstruction principle, general positioning principle and growth-type design theory, is represented firstly, which is based on the function-structure model. At the philosophical level, decomposition-reconstruction principle reveals the essence of invention-creation. At the theoretical level, general positioning principle illustrates the constraint law that each part of mechanical products must follow; At the method level, growth-type design theory expounds the general law of product evolution design on the basis of mirroring the biological growth mechanism. On this basis, combined the design modell-Zigzag modell of xiomatic concept process design, this paper presents the conceptual process design modell based on function-function-structure model-structure. The conceptual process design modell is top-down oriented, and takes the function-structure model as mapping media, what’s more, function decomposition and reconstruction is done synchronously. Design problem is a cognitive process, and design information increases gradually along with the expand of design process under the support of design knowledge, which reflect the discipline of human cognition and thinking; and also show the completion from the product prototype to conceptual design scheme, every stage of design all reflects the structural growth process of design object, which is a structural refining process. This modell is divided into product special layer, product general layer (i.e. mechanism layer), product base layer (i.e. standard parts layer), and the deeper the design level is, the lower of the product correlation of design knowledge and the worse of innovation ability are. At different design process levers, different design strategies need to be adopted.2) Function modelling is one of the key problems of conceptual design, and characteristics of functional information itself determine the expression difficulty in computer. Modelling of user requirements, characteristics of user requirements, and collection, organization and processing of demand are discussed, which make the modell of user function possible. Simultaneously, the paper discusses some concepts and definitions corresponding with the functional modelling, and redefines these concepts and terms, such as function, quality and performance etc., on the basis of learning and mirroring some scholars’ideas. An innovative functional information modell based on the analysis of functional expression modell proposed in current documents, is probed, which includes functional behavior expression set, functional behavior parameters set and functional constraint feature set, and it applies to the functional description of three-layer construction as product-level, transmission chain-level, transmission-level, also, which is quite flexible and can rerun concept expand in the course of reuse. Functional behavior set is the main motive power of functional decomposition; functional constraint feature set is the knowledge foundation of structure reconstruction. The decomposition-reconstruction process of functional information expression modell in design is illustrated; correlation factor modell of functional constraint is put forward and the effect, decomposition and reuse method of performance factor on decomposition-reconstruction is also analyzed. The concept provides possibility for raising each performance of products in the process of automatic design, which not only has great significance to the innovative design and adaptive design, also provides new ideas for the reverse conceptual design.3) Based on the decomposition-reconstruction and generalized positioning principle, the minimum information unit (i.e. function surface) of the whole lifecycle of conceptual design product is described in detail, and the function surface classification is introduced, and the relationship among function surface, structure and positioning is analyzed. On this basis, the paper expounds the basic information unit (i.e. function-structure model) of conceptual design product systematically, and discusses the effect that function-structure model has on conceptual design product is, meanwhile, realize the information transfer from function to structure in deeper levers using the function-structure model as physical carrier. Establishing the mapping model of function-function-structure model-structure, which makes the product information expression more complete, organization more flexible,and more rigorous, scientific in concept and theory. At the same time, the evolutionary growth process of function-structure model in the move of function is analyzed, and the general reasoning rule of the transmission chain design of function-structure model is introduced. Data structure of function-structure model uses object-oriented technology, and function-structure model coding uses variable-length, hierarchical scheme, which belongs to the classification coding system of characteristics of things. Function-structure model classification and coding is divided into three parts: identifier, SID code and functional characteristic code. SID code is the classification code of components and is an active type, when is driven by external news, SID code calls himself to carry out a retrieval. Based on the reverse engineering theory, the acquire method of parts function factor and conceptual structure factor on the basis of function-structure model is proposed, and the reconstruction method of function-structure model based on reverse engineering product design process is analyzed.4) On the basis of growth-type and axiomatic design theory, the conceptual design reasoning modell of mechanical products is built, which solves the mapping from function to function-structure model effectively. Aimed to the problems that design information of conceptual design phase is unable to quantify and design solution is unsure, the three-layer conceptual design principle to solve fuzzy evaluation system based on Delphi analytic hierarchy process (AHP), minimum information analysis method and sigma method is proposed. Optimizing the product conceptual design scheme on the whole when solve the morbid problem of function-structure mapping. PART-NET assembly modell based on virtual transmission chain is established, which conveys the assembly relation to part and part, surface to surface, which realizes the full association of parts. The evolutionary retrieval mechanism based on examples was put forward, matching degree weighted coefficient is determined by using the analytic hierarchy process to create movement and structural matching degree function, and retrieval process based on examples is illustrated, which solves the problems of design knowledge representation and entity structure transformation effectively and is helpful for the development of computer aided conceptual design tools.5) On the basis of studying these design theories and key technologies mentioned above, assembly-oriented computer aided conceptual design system-FM-BDARFAD is developed, creating process of product structure, which is product structure-oriented and supports the parallel design, is established, and the create and design process of product structure realizes the process from scratch and from small to large of parts, which really reflects the top-down design process. This idea based on growth-type design theory of the system starts from product design requirements, which creates product prototypes interactively, and goes through functional decomposition-reconstruction to obtain product conceptual structure scheme taking the transmission chain design as the core, and reflects product design lifecycle of design information from small to large, construction from disorder to order and from low to high. This system includes demand management module, function management module, scheme reasoning module, scheme assessment module, virtual simulation module,entity matching module, products reverse solving module, tolerance solution module, information management module, safety management module,and so on. Finally, taking the multi-functional lumbar spine traction bed as an example, this paper describes the functional decomposition and product evolution process in detail. Case study shows that establish the product process design modell supporting product conceptual design on the basis of function-function-structure model-structure mapping, which provides a new idea for the computer aided product conceptual design.更多还原